Means for producing current of reduced frequency



Dec. 22, 1931; I g, ROBERTS I 1,837,337

MEANS FOR PRODUCING CURRENT OF REDUCED FREQUENCY I Filed June 2, L928 Contact 6 makes before Contact r'eaks II II II I! n n I! u u i II II II II M ll II It ll ll INVENTOR LCEoerlis ATTORNEY Patented Dec. 22, 1931 UNITED STATES DELAND c. ROBERTS, or ToWAco; ew JERSEY, ASSIGNOR TO AMERICAN AND TELEGJAPH COMPANY, A CORPORATION, on NEW YORK PATENT OFFICE TELEPHONE MEANS FOR PRODUCING cUaRnn-ror REDUCED FREQUENCY Application filed June 2, 192 Serial No. 282,470.

This application is a continuation in part of my co-pending application'filed August 6, 1927, and given Serial Number2l1-,248.

This invention relatestoneans for pro- 5 ducing a reduced frequency, that is, a current alternating at a lower frequency than a basic current and more particularly to electrical circuit arrangements for dividing any basic frequency by any integer. r

10 It would be desirable, especially'ingexteh sivei systems of electrical circuitsinvolving electrical apparatus to great numbers, to make use of a standard frequency, This standard frequency would be available for controlling the speeds of machines andrcali brating oscillators, for instance. U

With a standard frequency in use, a requirement for many purposes is .a suitable device for reducing the standard or basic frequency to a lower frequency or anyone of a number of lower frequenciesthat is, for producing a current alternating at a lower frequency than thecurrent of the standard frequency. 7

The principal object of myinvention is the provision of simple circuit means forreducing a basic frequency (in the sense indicated above) by dividing it by any integer.

The accompanying drawing shows in a diagrammatic form a suitable circuit arrangement embodying my invention. The basic frequency is divided by five to illustrate the production of an odd submultiple and by six to illustrate the production of an even sub-multiple. i r I l The system specifically disclosed inflthe drawing consists essentially, in association with an alternating current generator, ofa re lay R- actuated by current of thebasic frequency and vibrating its armature in synchronism with this frequency, a polar relay R havingan armature associated with a source of direct current and designed to reverse the polarity thereof, a relay R controllingthe operationfand in part the timing of the polar relay, and a chain of relays R R R R, together with certain other features pertaining to the production of either a sub-multiple of the basic'fresub multiple of the basic frequency which is even, and switching means for includin in the circuit the elementor elements contri uting to the particularresult desired. Certain minor features and numerous advantages of the circuit arrangement of the invention will be disclosed and discussed below in connection with the detailed description of the op-' eration of the system. The number of relays in the chain 11 ,11 R R may be varied to produce a different division of the basic frequency, as will appear more clearlyhereinafter. I f It is deemed desirable to present first a dis cussion of the o eration of the system when an odd sub-multiple of the basic frequency is desired, and then to follow this discussion with a discussion of the operation of the system when an even sub-multiple of the basic frequency is desired. For the purpose'of clarityv of description the basic frequency may be termed f. The first operation tobe described is that which will produce the submultiple I. 5 I the secondoperation be discussed duce the sub-multiple If the circuit isto be used to produce the odd sub-multiple of the basic frequency f, the switch S is operated to closethe circuit be tween the contact 16 and w, the circuit being opened between contact 16 and y, and the switch S is closed to complete the circuit between contact 31 and :0; thus the relays R and R contribute to the operation of the will prosystem. If, on the otherhand, the even sub multiple of the basic frequency f is to bproduced, the switch S is operated to break the circuit between contact 16 and m andtoclose it between that contact and 1 and the switch S3 between contact 31 and w is opened; thus the relays R and R are eliminated from the active circuit,

quency which is an odd sub multiple, or a g It being understoodthat an odd sub-multiple of the basic frequency f, specifically the frequency is to be produced, the series of relay opera-- tions may be described in some detail as follows:

The relay R operates in synchronism with the current produced by the alternating current generator 1, and the armature of this relay is thrown between contacts 2 and once every half-cycle. Let it be assumed that armature rests on contact 3 and durin-' first half cycle is thrown to contact 2. ll l the armature touches contact 2, a circuit closed from the battery connected to the armature of the polar relay B through contact 22, contact 2, contact 25, contact 4, and the winding of relay R and relay R, is oper ated. Relay R locks in its operated position through contact 6 and contact 24 over the lefthand armature of relay R Likewise when relay R operates, the cl sing of contact 7 prepares a circuit including the winding of relay R and contact 5 clos .s, preparing in part a path to relay R One half-cycle ater,

ith reference to the basic frequenc 7 which is produced by the generator 1 and which con trols the operation of relay R, the armature of relay R goes to its back contact 3 and the circuit is closed from battery over the armature of the polar relay ll, contacts 22, 3, 27, 7, and 11, and the winding of relay R Upon the operation of relay R contact 8 is closed, compl ting the preparation of a path to relay R the closing of contact 9 completes a locking circuit for relay similar to the locking circuit of relay R described above, and the closing of contact 10 prepares in part a path to relay 11;. During the third halfcycle of the alternating current of the basi frequency, the armature of relay R again touches contact 2, and battery over the armature of relay R is connected in circuit with the winding of relay R the path being similar to those described above and readily traced. It should be borne in mind that when relay R, operated, the lead from contact- 25 was disconnected from contact 4; ed to contact 5. Similarly, the operation of relay R throws the armature at the extreme right from contact 12 to contact 13 and propares in part a path through to to relay E Also the relay R is locked through contact i l, and contact 15 closed to complete a circuit to relay 11,. During the fourth half-cycle of the current of frequency 7", the armature of winding of relay over contact 18 ated, with that relay, and contacts 16 and l? are closed. The relay ll, is locked over contact 17, and the closing of contact 16 completes the circuit path to relay \Vith reference to relays R R R and R. in order, it should be noted that contact 6 must make before contact l breaks, contact 9 must make before contact 11 breaks, contact 1% must make before contact 12 breaks, and contact 17 must make before cont" ct l8 breaks.

When the armature of :clay ll goes to contact 2 during the fifth half-cycle, a circuit is completed from battery over the armature of the polar relay It and contacts 2, 25, 5, 8, 13, andv 1G to the winding of relay Ti and this relay is operated. Likewise, a circuit, as just described, is closed from battery over contact 31 to the winding of relay 1%,.

The operation of relay ll in response to the fifth operation ol relay ll, opens contact 24: and thus breaks the locking circuit for the relays of the chain R R R and R Lila Wise, relay operation closes contact 23 and opens contact The polar relay R has two windings ll, and V and an armature which, as indicated above, makes alternating contacts to reverse the polarity of the battery, this armature be ing shown in the drawing in contact with the plus pole of the battery. The relay winding V is so connected that current through it will cause the armature of the relay to go to the contact opposite that on which it is resting; with the condition as indicated in the drawing, current through this winding will cause the armature to go from the right-hand contact to the left-hand contact this opera tion, of course, reversing the polarity of the battery. The Winding W is so connected that current through it will have an effect opposing the effect of current through the winding l/V When relay ll is operated as a result of the fifth operation of relay R, the battery is removed from the armature of relay ll and is connected hrough a resistance 3 and th winding "W of polar relay It, upon the opening of contact 22 and the closing of contact 28. The current through winding ll, thro the armature of relay it from the righthaud contact (as shown in the drawing) to the leflihand contact. l Vhen this latter contact is made, a charging current flows through the condenser C and the winding W this mom n tary charging current serving to hold the armature of relay ll lirinly on the left-haiul contact until relay R releases. In order that this operation may be effected, the resistance 33 must be of such value that the ellect of the momentary current through condenser C and the winding W will i e greate than the effect of the operating current through resistance 33 and the winding The resistance 34 serves as a leak to discharge the condenser C during the interval when the armature of relay l t is between its two contacts. lesistance 84; is of such. value that steady static current will hold the armature of relay R" on its contact when relay R operates, current through the winding lV ,large enou'gh'to overcome the effect of the current in winding W will move the armature to the opposite contact.

As has beenstated above, the-fifth opera; tion of relay R causesnot; only the operation of relay R but alsothe operation ofrelay R A Since thecoinpletion ofthe first cycleof operations of relays B B R R and R 'finds the armature of relay R touching contact 2, and since,of course, the pro'ductionof the reduced frequency is basedon repeated cycles of operations of these relays, it now becomes necessary, in the case of the'production of an odd sub-multiple of'the frequency f, to provide for the repeated operationof the relays of the chain in the proper se uence; this-may be done by aninterchange' 0. the connections from the contacts2 and 3. Thisinterchan'ging of connections is the function of-the relay 11 As' will appear hereinafter, the release at the proper time of relay R is the function of relay R vVhen relay R operates, in response to the fifth operation of relay R, contact is opened and contact 26 closed, and likewise, contact 27 is opened and contact 28 closed; there is thus produced the desired interchan e of connections from contacts 2 and 3. Also, upon the operation of relay R the contact 29 is closed (before contact 31 opens), and a locking circuit is completed through battery, contact 29, winding of relay R and contact 32.

In addition, the relay operation breaks contact at 31 in the original operating circuit of relay R and by the closing of contact 30 completes a circuit from battery through the winding of relay R over contact 30 and switch S to the point an associated. with switch S. If this circuit is traced beyond an it appears of course, that it is the same circuit which controls the operation of relays R and R Relay R does not operate when relay R operates because positive battery is connected to both ends of its windings, as an examination of the drawing will show.

The interchange of connections 25 to 26 and 27 to 28 having been made by the operation of relay R it will now readily be understood that the sixth, seventh, eighth, and ninth half-cycles of the alternating current of frequency i will, through the corresponding operations of relay R, cause the relays R R R and R to operate in the proper sequence. More specifically, the first time in the second cycle of operations that the armature of relay R touches contact 3, relay R will operate, the first time contact 2 is touched relay R will operate, and so on. After the tact at the right. As will readily be understood, the operation of relay R" is maintained by repeated cycles of operations of the relay chain R1 to-R the'relaysof the 'chain being putin conditionqfor each new cycle 7 of operations bythe operationof relay, R which breaks the locking circuits at contact 24,: and'by the operation of relay R as de-' scribed above. i

It is'necessary, of course, that relay R be released after the tenth half-cycleand the t'enthoperation' of relay R." This tenth 'operation' of 'relayjRnot only operates relay R, but also completes'an operating circuit for relay Thiscircuit is traced as follows: fr'oinbattery over the armature of relay R whichbattery' is now negative-over contacts 22, 3, 28, 5, 8, 13 and 16, switches S and S and contact 30 throughthe winding of relay R to positive battery. Since the battery at the two ends of the relay winding is no longer positive in "both cases but is negative atone end and positive at the'other, relay R willnow operate and-break the locking circuit of relay R at contact 32. As a result, the relay R releasesgandthe original con nections from contacts 2and 3 are restored.

Thus the system is placedin condition for the third cycle of operations of relays R to systemewhen thedesired result is the production of; an even'sub-multipleof the basic fre quency 7. The system is placed incondition for suitable operation by the throwing of the switch Si from ma andthe opening of I switch S5. These switching operations add the circuits associated with relay R to the system-that is, they add one relay to the It remains to discuss the operation of the operate in order, as has been described above U in connection with the production of the odd sub-multiple. The operation of relay B, through the closingof contact 16 now completes a circuit from battery over the armature of relay R torelay R5 through contact 19 associated with the last named relay. Relay. R themupon the fifth operation of relay R, is actuated, locks up through contact 21 and closes contact 20 tofpre'parethe necessary path from battery over the armature of relay R to relay B In response to the operation of relay R aswas shown to be the case in the abovejdiscussion, the polar relay R. operatesto throw its armature from the positive battery contact at the right to the negative battery contact atthe left. Since there are nowfiverelays the chain R R511 R and R (it being rememberedthat relay R operates on the next half-cycle, that is, the

sixth) we now fi'nd that at'the completion of the first cycle of operations the armature of relay R is touching the back contact 3 where it was originally. Accordingly, the system is placed in condition for the next cycle of operations by the mere breaking of the chain relay locking circuits at 24 in response to the operation of relay R and no interchange of the connections from contacts 2 and 3 is required. It should be noted, in connection with relay R that contact 21 must make before contact 19 breaks.

It will now be clearly understood that in the specific case discussed above, of the operation of the system to produce an odd submultiple of the basic frequency 7, the armature of the polar relay R will reverse the battery polarity so as to produce an output frequency of that is, the basic frequency has been divided by 5. Likewise, it will readily be understood that when the speci tic circuit shown is altered to include relay R in the chain of relays, to give an odd number of relays in the chain, the output frequency produced by the operation of relay R will be It is readily understood, of course, that the basic frequency 7 may be divided by any other integer, odd or even, if the number of relays in the chain R R R R is changed, the output frequency being where f represents the basic frequency and a the number of relays in the chain indicated. In other words, the frequency f may be reduced to the frequency by connecting in the relay chain relays which are n1 in number.

Looking exclusively at the operation of the system as it affects the timing of relay B, it is seen that relay R may be considered as one relay of the chain, in which case the total number of relays in the chain equals the integer by which the basic frequency is divided.

\Vhile the applicants invention has been discloses in a specific embodiment which is deemed desirable. for the purpose of clear illustration, it will be understood that the scope of the invention is not limited thereby but is determined by the appended claim.

What is claimed is:

In association with a source of alternating current of a basic frequency of F cycles, an

electrical system or producing a current alternating at a frequency of cycles, said system comprising a first switching means responsive to the reversals of the current of the basic frequency, a source of output current, a second switching means for alternating the polarity of said source of output current, a relay for controlling the operation of said second switching means, and a chain of relays numbering N-1 interposed between said first switching means and said controlling relay, the relays of said chain and the controlling relay operating successively in response to the successive operations of said first switching means.

In testimony whereof, I have signed my name to this specification this 1st day of June, 1928.

LELAND C. ROBERTS. 

